In a room of 30 people, every person shakes hands with every other person exactly once. How many total handshakes take place?
435
The formula for handshake combinations is n(n - 1) / 2. For 30 people, this is (30 x 29) / 2 = 870 / 2 = 435.
About this riddle
Math riddles hide a calculation inside a short story. Pull out the numbers, work out what is being asked, and watch for a trick such as a unit change.
Difficulty: Hard. More like this: Math riddles with answers or try Target 24 for a different kind of puzzle.
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